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Suggested Citation:"6 Monitoring and Analytical Issues." National Research Council. 2010. Review of Closure Plans for the Baseline Incineration Chemical Agent Disposal Facilities. Washington, DC: The National Academies Press. doi: 10.17226/12963.
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6
Monitoring and Analytical Issues

OVERVIEW OF CLOSURE STRATEGY

Depending on the particular site, the planning for closure of the chemical agent disposal facilities that are the subject of this report is designed to achieve Resource Conservation and Recovery Act (RCRA) clean closure according to either industrial or residential standards (Bechtel Aberdeen, 2007; EG&G, 2009b). Facility closure is complete when these conditions are met: all waste management units have been decontaminated, dismantled, and demolished; all ancillary buildings are dispositioned per contractual agreements; and the regulatory authority agrees that closure performance standards have been achieved. The facility closure process includes management of surplus buildings and equipment and waste generated during processing operations.

During closure operations, the concern with respect to potential agent exposure primarily deals with occluded spaces. These are confined volumes within a system, structure, or component that were exposed, or potentially exposed, to liquid agent and therefore have the potential to contain some quantity of agent-contaminated liquid (Bechtel, 2006; Herbert, 2010; Battelle Memorial Institute, 2010; Parsons, 2009).1 Although in most instances the quantity of agent that may be encountered in such spaces is likely to be small, it takes only a small amount of agent to generate an exposure incident. Therefore, accurate measurement of residual agent is a critical activity in the closure processes.

The challenges posed for closure of chemical agent disposal facilities relate to the measurement of agent quantities that remain in waste media, structures, and equipment. Sampling and analysis of many of these materials is difficult and may not be suited to conventional approaches used for measuring agent contamination. Examples include concrete, polymeric materials, and other waste solids, as well as metal equipment parts. In all of these, small amounts of agent can be retained in occluded spaces or sorbed onto porous materials. Moreover, the agent will not be uniformly distributed, which means that using a reasonable sampling plan structured on a strictly statistical basis may be prone to underrepresentation of the extent of contamination. In view of the extreme toxicity of agents and certain degradation products, there may be significant consequences from misidentifying or underestimating contamination. These conditions carry the additional consequence of high costs and delays derived from the need to collect and analyze many samples.

A potentially sensitive and protective means of identifying residual agent in materials and equipment during closure is the unventilated monitoring testing (UMT) (Herbert, 2009).2,3 This is a variation on the headspace monitoring approach traditionally used by

1

Battelle, “Occluded Space Training,” presentation to UMCDF, March 3, 2010, provided to the committee by Raj Malhotra, Deputy, Risk Management Directorate, CMA, via email to Nancy Schulte, study director, May 3, 2010.

2

Carla Heck, Project Manager, URS, “Programmatic Closure Document Development and Status of Closure Planning,” presentation to the committee, January 26, 2010.

3

Richard Sisson, Senior Research Scientist, Battelle, “Closure Tips and Tricks,” presentation to UMCDF, provided to the commit

Suggested Citation:"6 Monitoring and Analytical Issues." National Research Council. 2010. Review of Closure Plans for the Baseline Incineration Chemical Agent Disposal Facilities. Washington, DC: The National Academies Press. doi: 10.17226/12963.
×

the Army for clearing material that was suspected to be agent contaminated.4 What is measured by UMT is the agent in the atmosphere associated with the location being evaluated, which requires that that agent be present in the gas phase. UMT involves enclosing the room or object to be sampled with a plastic barrier that prevents diffusion and allows concentrations to build to the point where the agent can be readily detected by current near-real-time monitoring equipment. The method is designed to protect against airborne exposures to agent, but due to the vapor pressure of the agents and the sensitivity of the analyses, it is also used to infer the presence or absence of liquid agent. UMT, in sampling headspace, can be used for evaluating contamination in many different types of wastes and media. It does not require the time-consuming collection of solid samples and the extractive analyses thereof, which are also subject to uncertainties arising from nonuniform contamination distribution, a feature inherent to closure situations. UMT has been successfully applied in the closure of both the Aberdeen and the Newport facilities (Battelle Memorial Institute, 2010; Parsons, 2009).5,6

Chemical or physical phenomena that limit the volatilization of the agent are a potential limitation of the UMT approach, and occluded spaces are a particular concern in this regard. Any agent occupying occluded spaces (for example, agent trapped in small cracks or sorbed into porous materials) may not volatilize sufficiently for headspace measurements. Occluded spaces can prevent (a) contact of the agent with a decontamination solution; (b) volatilization of agent; and (c) subsequent detection using UMT.

In this chapter, the strengths and weaknesses of both conventional analyses and UMT for monitoring equipment and spaces undergoing closure are considered, with a primary focus on identifying approaches that maximize the utility and effectiveness of UMT during closure. Utilization of physical sampling followed by extractive analysis is also briefly discussed.

Properties of Agents Significant to Closure Situations

The chemical and physical properties of chemical agents affect their toxicity and their detectability. In the context of closure, agent volatility and hydrolysis behavior are the two most significant properties. While all three of the agents processed at the baseline chemical agent disposal facilities are considered semivolatile liquids, the nerve agent GB has a markedly higher vapor pressure (2.9 mm Hg at 25oC), consistent with faster rates of volatilization (Reutter, 1999). In addition, GB has the greatest ability to diffuse through porous or permeable materials, and hence it is less likely to survive for long periods of time on surfaces or in near-surface environments. Mustard is relatively nonvolatile, with a vapor pressure of 0.11 mm Hg at 25ºC. The nerve agent VX has an even lower vapor pressure (only 0.0007 mm Hg at 25ºC) (Reutter, 1999).7 In situations in which mustard or VX fills cracks or diffuses into permeable materials, volatilization may be inhibited, but subsequent disturbances of the system could expose intact agent. This could produce a potential for exposure from volatilization, or more likely from direct dermal contact. Migration or volatilization of mustard or VX from porous or permeable surfaces may not occur.

Chemical agent residues may also become depleted by chemical degradation processes that are principally hydrolysis reactions and that result in significant agent detoxification (with a salient exception of VX as described below). Since the majority of hydrolysis reactions produce degradation products having low toxicity, further discussion is not provided here; additional details can be found in Appendix C. However, VX hydrolysis via P-O bond cleavage is not in this category: this reaction produces S-(N,N-diisopropylaminoethyl) methylphosphonothioic acid (known as EA-2192 in the Army vernacular), which is a compound that retains much of the neurotoxicity of intact VX. Hence, the possible presence of this compound is an ongoing source of concern (Yang et al., 1990; Munro et al., 1999).8 However, concerns related to EA-2192 are reasonably mitigated by the following considerations:

tee by Raj Malhotra, Deputy, Risk Management Directorate, CMA, via email to Nancy Schulte, study director, May 3, 2010.

4

Headspace is the gaseous atmosphere associated with an object normally confined by an enclosure or container.

5

Brian O’Donnell, Chief, PMCSE Secondary Waste and Closure Team, CMA, “CMA Programmatic Closure,” presentation to the committee, January 27, 2010.

6

Jerry Spillane, Closure Engineer, NECDF, “NECDF Closure Lessons Learned,” presentation to the committee, October 20, 2009.

7

In the context of this report, bis-(2-chloroethyl) sulfide, or sulfur mustard, is referred to as H, HD (distilled mustard), or HT (distilled mustard mixed with bis-(2-(2-chloroethylthio)ethyl) ether).

8

The state of Utah requires measurement of EA-2192 to ensure detoxification to closure standards (see Chapter 5).

Suggested Citation:"6 Monitoring and Analytical Issues." National Research Council. 2010. Review of Closure Plans for the Baseline Incineration Chemical Agent Disposal Facilities. Washington, DC: The National Academies Press. doi: 10.17226/12963.
×
  • EA-2192 has extremely low volatility and therefore poses virtually no inhalation hazard.

  • EA-2192 does not diffuse through the skin barrier (as does VX).

  • Hydrolysis of EA-2192 proceeds fairly rapidly, with a rate constant on the order of that of the parent compound (0.1 day–1) (Kaaijk and Frijlink, 1977; Verweij and Boter, 1976).9

The rate of VX degradation is expected to be fast (on the order of 0.1 day–1), which suggests that residual agent concentrations are likely to be low10 unless protected in an occluded environment. The degradation rates of G agents will be even faster than those of VX.

RESIDUAL AGENT MEASUREMENT IN CLOSURE

Closure operations at chemical agent disposal facilities are to be conducted in a manner that is intended to eliminate the potential for exposure to agent and hazardous by-products. Each facility will have to comply with closure standards for waste, residues, and media that may be different depending on individual state regulations.

Closure operations are conducted in a series of steps, the explicit definition of which can vary somewhat depending on the site and the individual area undergoing closure. However, all closure operations have common activities, which in general include (Herbert, 2009; Battelle Memorial Institute, 2010):11,12

  1. Identification of all areas of historical contamination (URS, 2009; EG&G, 2009a).13 This phase is designed primarily to document the history of chemical agent contamination in assessing whether the component or area in question may have come in contact with agent and, if so, in what form. This phase is used to guide where and how occluded space surveys should be conducted, and it may have value for correlating historical exposure events with residual agent when retrospectively compared with the results of UMT.

  2. Identification and elimination of occluded spaces. This includes conducting an occluded space survey, which is designed to identify locations where agent liquid or vapor may have accumulated, in order to ensure that effective decontamination takes place.

  3. Applying decontamination methods. This includes the preparation of an occluded space decontamination plan and identification of the appropriate methods to be used for decontamination. These methods will be dependent on the agent and the equipment or material to be decontaminated. Procedures to document decontamination are also defined, as are the future uses planned for the equipment and the appropriateness of the decontamination criteria employed. This step also encompasses decontamination of equipment and areas.

  4. Removal of equipment or leave in place. Equipment removal requires dismantling and decontamination of the equipment. These activities, as well as the decontamination of areas, are guided by the planning done in the previous phases with a goal of achieving maximum efficacy and with a focus on areas identified in the occluded space surveys.

  5. Verification of equipment decontamination. This may include wipe testing, extractive analysis, or vapor monitoring. Because many pieces of equipment are not appropriately characterized by wipe testing or extractive analysis, this normally involves tented headspace monitoring of the equipment to ensure that airborne concentrations are less than 1 VSL (<1 vapor screening level), indicating that any residual contamination is minimal.14

9

Rate studies of degradation of EA-2192 are few, and rates will certainly vary depending on the specific temperature, moisture present, and the surface with which the compound is in contact.

10

See Appendix C for citations from the Livermore National Laboratory group, which indicate that rates of 0.1 day–1 can be expected for VX, as well as Groenewold (2010).

11

Brian O’Donnell, Chief, PMCSE Secondary Waste and Closure Team, CMA, “CMA Programmatic Closure,” presentation to the committee, January 27, 2010.

12

Richard Sisson, Senior Research Scientist, Battelle, “Closure Tips and Tricks,” presentation to UMCDF, provided to the committee by Raj Malhotra, Deputy, Risk Management Directorate, CMA, via email to Nancy Schulte, study director, May 3, 2010.

13

Teleconference with Brian O’Donnell, Chief, Secondary Waste, Closure Compliance and Assessments, CMA; Amy Dean, Environmental Engineer, Project Manager for Elimination of Chemical Weapons, CMA; Jeffrey Kiley, Chief, Quality Assurance Office, Risk Management Directorate, CMA; and the committee; May 4, 2010.

14

A vapor screening level (VSL) is an internal control limit used to clear materials for off-site shipment based on agent concentration in the atmosphere surrounding the materials. The VSL for each agent is set to the short-term exposure limit (STEL)—the

Suggested Citation:"6 Monitoring and Analytical Issues." National Research Council. 2010. Review of Closure Plans for the Baseline Incineration Chemical Agent Disposal Facilities. Washington, DC: The National Academies Press. doi: 10.17226/12963.
×
  1. Monitoring to demonstrate adherence to appropriate closure performance standards. Physical sampling followed by extractive analyses may be employed, but unventilated area monitoring is primarily used as a more sensitive indicator of residual contamination.

  2. Demolition. Destruction of the physical plant structure, including components found within it, is conducted upon successful completion of all previous steps.

Throughout this process, measurements of residual agent levels constitute a critical activity. Specific objectives of residual agent monitoring are as follows:

  • Protecting the workforce during disassembly and demolition;

  • Supporting accurate decision making with regard to disposition of secondary wastes, residues, and media;

  • Ensuring that contaminant levels at the site are at or below clearance levels; and

  • Protecting the general public.

The analytical approaches used to demonstrate adherence to the standards related to the above objectives fall into two categories: either sampling and extractive analysis or vapor space monitoring, which is achieved through tented headspace monitoring (for individual pieces of equipment) or unventilated area monitoring. Procedural details employed for the sampling and extractive analyses can vary substantially depending on the agent, the degradation product, or the matrix being examined. Similarly, temporal variations in the headspace and unventilated area monitoring procedures are employed to cover different sampling volumes that are related to the size of the equipment or room to be monitored. The analytical methods employed, and their variants, must satisfy required method quality control specifications, including accuracy, precision, and detection and quantitation limits for all matrices. Differences in the material and equipment matrices may cause deviations in method performance; these are discussed in more detail below. Analytical method modification may be needed to achieve state-specific closure standards; in these cases, significant time and effort may be required to develop and achieve regulatory approval of modifications.

Sampling Followed by Extractive Analysis

Closure requires that waste, residues, media, buildings, and equipment be decontaminated to concentrations below the applicable closure performance standards appropriate for subsequent facility dismantling and disposal. Similarly, soil at the site must be demonstrated to be below required closure performance standards. Analysis of solid samples from these environments has traditionally been based upon extractive analysis of materials to ensure adherence to closure standards. Extractive analysis has been used both to show that concentrations are below RCRA limits and to establish that decontamination is effective (Bechtel Aberdeen, 2007; EG&G, 2009b).15

The appropriate closure standards that may be applied at various facilities may differ, but in general, the standards should recognize that closure will result in waste disposal or recycling of material and equipment. This suggests that the most relevant standards are for occupational exposures. But specific closure standards will be determined on a state-specific basis.

At the Umatilla Chemical Agent Disposal Facility (UMCDF) there is a regulatory requirement that all materials sent off-site, such as construction debris, must be cleared using sampling and extractive analysis. The same is true of the soil sampling to be carried out to certify that the site meets closure requirements. The sampling and extractive analysis of concrete debris presents particular issues due to the difficulty of collecting and analyzing representative samples. Thus, unventilated air monitoring may be a more reliable means to identify the presence of residual agent. There also appears to be a difference of opinion between the EPA and the Oregon Department of Environmental Quality (ODEQ) as to the proper procedure for analyzing concrete debris.16 UMCDF has ODEQ’s approval for a method that includes pH adjustment before extraction, while the EPA method does not allow for pH adjustment. If the EPA method is to be adopted it will require

concentration to which workers can be exposed continuously for a short period—established by the Centers for Disease Control and Prevention (Federal Register, 2003a, 2003b).

15

CAMDS/TOCDF Closure Team, URS, “CAMDS/TOCDF Closure Status Implementing Programmatic Closure Approach,” presentation to the committee, January 27, 2010.

16

Personal communication between Mike Daniels, closure manager, UMCDF, and Peter Lederman, committee chair, June 16, 2010.

Suggested Citation:"6 Monitoring and Analytical Issues." National Research Council. 2010. Review of Closure Plans for the Baseline Incineration Chemical Agent Disposal Facilities. Washington, DC: The National Academies Press. doi: 10.17226/12963.
×

an estimated year to carry out laboratory validation and ODEQ acceptance. This type of challenge can become a major impediment to meeting schedules.

Although sampling and extractive analysis is available as a means to define the status of agent decontamination for closure and to guide the disposition of waste, residues, media, equipment, and buildings potentially contaminated with agent, the problems of representative sampling, accuracy, time requirements, and cost of extractive analysis remain. Due to the difficulty of measuring concentrations in porous solids, particularly construction debris and equipment, the Army has chosen to pursue alternative measurement approaches, namely, headspace monitoring of individual pieces of equipment and unventilated area monitoring for buildings and large areas. As noted previously, these are collectively referred to as unventilated monitoring testing (UMT); they are discussed below. States may nevertheless require sampling and extractive analyses in some cases, such as for clearing wastes for transportation off-site to a treatment, storage, and disposal facility.

Unventilated Vapor Monitoring: An Alternative Approach

The Army has developed alternatives to sampling and extractive analysis. These alternatives use unventilated monitoring of the vapor space around equipment and areas, which reduces the effects of heterogeneity and matrix interferences. Briefly, UMT involves sealing off the equipment or area to be tested; ensuring that the temperature within the sealed volume is 70ºF or above; and then monitoring the vapor space within the sealed volume. If volatilized agent is present, this approach allows its concentration to build up by increasing volatilization and preventing diffusion to other parts of the atmosphere. The performance of the UMT will be dependent upon maintaining the specified temperature, which will require actively heating the areas using space heaters and careful temperature monitoring, particularly during the colder months. The result is that concentrations measured in the UMT are much higher than in a comparable ventilated test, and for this reason, UMT would be conservatively protective of the workforce.

The unventilated vapor monitoring is applied to both individual pieces of equipment and to buildings and areas. When applied to individual pieces of equipment, the approach involves sealing with plastic sheeting (i.e., tenting of the equipment) and monitoring the vapor concentration of agent after a fixed period of time dependent upon the tented volume (i.e., 15 minutes for a tented volume equal to or less than 0.8 m3, 45 minutes for a tented volume between 0.8 and 20 m3, and 4 hours for a tented volume in excess of 20 m3). The vapor concentration within the sealed volume at the end of the hold time must be less than the vapor screening level. The VSL for each agent is set at the short-term exposure limit—the concentration to which workers can be exposed continuously for a short period—established by the Centers for Disease Control and Prevention (Federal Register, 2003a, 2003b). The use of a standard of 1 VSL in a sealed environment ensures that concentrations much less than 1 VSL would be observed in a ventilated environment.

In buildings or large areas, the area is first subjected to ventilated monitoring over a period of 12 hours to ensure that the VSL is not exceeded before initiating the more severe unventilated test. The area is then sealed to the extent possible and the unventilated monitoring begun. At CAMDS, for example, the unventilated monitoring must show that the concentration does not exceed 1 VSL during any 4-hour period. If time-averaged sampling is used, this means that an average of 0.5 VSL will not be exceeded in any 4-hour period (i.e., assuming a linear rate of increase during the 4 hours). Sampling over multiple periods may be needed to document conformance to closure standards (e.g., 36 hours for CAMDS as per procedure PRP-CAM-002), but the standard remains 1 VSL in any 4-hour period.

The UMT is focused on airborne pathways of exposure and is used to compare potential worker exposure to worker population limits (WPLs) and potential public exposure to general population limits (GPLs). That is, the agent release rate that might lead to 1 VSL within the unventilated monitoring area is such that WPL would not be exceeded in a ventilated area and GPL would not be exceeded outside the work area. As with the VSL/STEL, the WPL and the GPL are set by the Centers for Disease Control and Prevention (Federal Register, 2003a, 2003b). The airborne pathway is the primary path of exposure to residual agent since the demolition strategy is designed to eliminate contact exposure to agent in liquid or solid phases (i.e., areas of potential contamination are subjected to decontamination) and since the facility destruction is done mechanically. Airborne sampling also can be a sensitive indicator of the presence of agent, but only as long as occluded spaces are properly identified and eliminated

Suggested Citation:"6 Monitoring and Analytical Issues." National Research Council. 2010. Review of Closure Plans for the Baseline Incineration Chemical Agent Disposal Facilities. Washington, DC: The National Academies Press. doi: 10.17226/12963.
×

even though the precise location of the contamination is unknown. Measurement of airborne agent in the headspace can reduce analytical complexity because it effectively samples the entire environment being sampled, and it avoids problems with low extraction efficiency and high chemical background and interference that can accompany an extractive analysis. To date, UMT has been approved for use at CAMDS by the state of Utah.

The UMT approach maximizes the concentrations of agent in the sampled headspace by allowing the concentration to build up in the absence of air exchange, thus making measurements of vaporized agent concentrations easier. This approach thus takes advantage of the stringent precision and accuracy capabilities of the agent air monitors.17,18 The measured values provide an estimate of agent release rate, which can then be used to estimate maximum airborne exposure in a ventilated configuration. The approach is attractive because it does not require extensive analysis (i.e., sample collection and extraction). UMT is easy to apply in the field and is relatively rapid, and therefore can be implemented with relatively minimal effort. The waste acceptance criteria are straightforward data quality objectives (in particular, detection limits to <1 VSL and avoidance of false negatives).19

The acceptably protective airborne limits of exposure to agents for workers (the WPLs) and for the general public (the GPLs) are shown in Table 6-1, together with the corresponding vapor screening level (VSL-STEL) used to evaluate airborne exposures in UMT measurements.

The UMT is designed to ensure that monitored items or areas will successfully meet WPL and GPL levels in a ventilated configuration when the tented or unventilated concentration is maintained below 1 VSL. In the event of agent measurement above the VSL, the area is decontaminated (or decontaminated again), and airborne concentrations are again measured in a ventilated configuration. If vented monitoring meets the <1 VSL criterion, a final unventilated area monitoring is performed. Measured UMT concentrations <1 VSL will ensure that exposure concentrations are greater than WPL in the working area and greater than GPL outside the working area. The previously described seven steps of the approach are designed to ensure that mass demolition of areas and equipment is limited to only those materials that have been decontaminated of agent or have been otherwise cleared. The approach ensures that workers are not exposed to vapors in excess of the WPL and the general population to vapors in excess of the GPL, but it does not directly address direct contact exposures. The effectiveness of the monitoring procedures to support this alternative testing protocol will be discussed in the next section.

ASSESSMENT OF MONITORING PROCEDURES

The overall monitoring procedure involves ventilated workplace monitoring (near-real-time measurements); occluded space identification and decontamination as needed; and, finally, UMT.

Assessment of Workplace Monitoring, Ventilated Environment Configuration

Near-real-time monitoring (i.e., having a response time of approximately 3 to 15 minutes) is used in areas where the presence of agent is possible (NRC, 2005b). Miniature Chemical Agent Monitoring Systems (MINICAMS) are used at the Tooele Chemical Agent Disposal Facility (TOCDF) for this purpose, while automatic continuous air monitoring systems (ACAMS) units are used at CAMDS.20 The same types of instruments are used at the other baseline disposal facilities. Confirmation monitoring is used to validate or invalidate a positive result from another monitoring system, such as MINICAMS and ACAMS, and is accomplished with the depot area air monitoring systems (DAAMS), which employs variable sampling times. The DAAMS backs up the MINICAMS and ACAMS and reduces false positives.21 These systems

17

Richard Sisson, Senior Research Scientist, Battelle, “Closure Tips and Tricks,” presentation to UMCDF, provided to the committee by Raj Malhotra, Deputy, Risk Management Directorate, CMA, via email to Nancy Schulte, study director, May 3, 2010.

18

CAMDS/TOCDF Closure Team, URS, “CAMDS/TOCDF Closure Status Implementing Programmatic Closure Approach,” presentation to the committee, January 27, 2010.

19

Richard Sisson, Senior Research Scientist, Battelle, “Closure Tips and Tricks,” presentation to UMCDF, provided to the committee by Raj Malhotra, Deputy, Risk Management Directorate, CMA, via email to Nancy Schulte, study director, May 3, 2010.

20

Thaddeus Ryba, Site Project Manager, TOCDF, “TOCDF Introduction (DEMIL-101),” presentation to the committee, January 26, 2010.

21

Thaddeus Ryba, Site Project Manager, TOCDF, “TOCDF Introduction (DEMIL-101),” presentation to the committee, January 26, 2010.

Suggested Citation:"6 Monitoring and Analytical Issues." National Research Council. 2010. Review of Closure Plans for the Baseline Incineration Chemical Agent Disposal Facilities. Washington, DC: The National Academies Press. doi: 10.17226/12963.
×

TABLE 6-1 Airborne Exposure Limits for GB, VX, and H, and Ratios of Worker Protection Limit and General Population Limit to Vapor Screening Level

Agent

VSL (mg/m3)

WPL (mg/m3)

WPL/VSL

GPL (mg/m3)

GPL/VSL

GB

0.0001

0.00003

0.3

0.000001

0.01

VX

0.00001

0.000001

0.1

0.0000006

0.06

H

0.003

0.0004

0.13

0.00002

0.0067

NOTE: The ratio of WPL to VSL and the ratio of GPL to VSL provide an indication of the magnitude of the respective WPL and GPL as a fraction of VSL.

SOURCE: NRC, 2005a; Battelle Memorial Institute, 2010; Washington Demilitarization Company, 2010.

comprise the continuous emissions monitoring systems (CEMS) for the sites.

Workplace monitoring measures actual exposures during operations and closure activities and should be used to confirm that acceptable closure standards have been met. It does not provide pre-demolition standards for decontamination, however, nor does it predict the potential for exposure during closure and dismantling activities. It is toward the latter goal that occluded space surveys and unventilated monitoring tests are directed.

Assessment of Occluded Space Identification for Decontamination

The occluded space survey is a key step in the unventilated monitoring test and the ultimate clearance of the site. As such, it is important that it be carried out very carefully and uniformly at all sites.

As previously indicated, occluded spaces are confined volumes within a system, structure, or component that were exposed, or potentially exposed, to liquid agent, and thus have the potential to contain small quantities of agent or agent-contaminated liquid (Battelle Memorial Institute, 2010; Herbert, 2010; Parsons, 2009; Washington Demilitarization Company, 2010). An example is found at the former Newport Chemical Depot (Indiana) facility for the production of the nerve agent VX, in piping that was not knowingly exposed to agent but in fact had residual agent contamination.22 Piping could represent an occluded space if capped, or merely by slow diffusion rates from an interior run to an opening to the ambient atmosphere (NRC, 2005a, pp. 16-26). Occluded spaces can potentially trap liquid agent, prevent contact with a decontamination solution, and prevent agent vaporization, and hence prevent detection during unventilated monitoring. Some common examples of occluded spaces include internal cavities of pumps and other equipment, cavities or cracks in concrete, internal sections of closed pipes and other systems, flat parallel surfaces in close proximity to each other, pipe and tank supports, and caulking seals around equipment supports and concrete joints.

Occluded spaces can be present in clean and screened material (<1 VSL); this includes decontaminated rooms within facilities and materials such as waste, residues, media, or decontaminated equipment removed for disposal. Of particular concern are items and areas that were potentially contacted by high concentrations of agent, either in liquid form or in vapor form at concentrations above the immediately dangerous to life and health (IDLH) levels.23 Past exposure to high vapor concentrations does not necessarily lead to significant liquid entrapment, but using an IDLH vapor concentration as an indicator of a need for special decontamination procedures is conservative (protective).

Occluded space teams (OSTs) have the responsibility for identifying occluded spaces and are the key to finding agent that might not be identified by other means. That is, extractive testing may not involve testing of the specific space containing the occluded liquid; likewise, vapor testing is more likely to detect the presence of occluded agent, but even that may not be successful if the agent is completely contained or tightly sorbed into the material. Accordingly, identification of occluded

22

VX degradation products were found in a 0.5-inch nitrogen line at NECDF in February 2004. The nitrogen had been used to purge tanks and reactors, for transferring liquids using pressure, and in the munitions filling process. Contamination of nitrogen systems is not uncommon in the petrochemical industry. It can occur if the supply pressure of the nitrogen system is not designed to be greater than the maximum system pressure or if the nitrogen supply failed during the operation of the process.

23

IDLH values are 0.1, 0.003, and 0.7 mg/m3 for GB, VX, and HD, respectively (NRC, 2005a).

Suggested Citation:"6 Monitoring and Analytical Issues." National Research Council. 2010. Review of Closure Plans for the Baseline Incineration Chemical Agent Disposal Facilities. Washington, DC: The National Academies Press. doi: 10.17226/12963.
×

spaces requires significant expertise and thoroughness that are achieved in the form of a multidisciplinary team trained for this extremely important purpose (Battelle, 2010; Herbert, 2010).24

The Army utilizes contractor experts for training the OSTs because of the diversity of possible occluded spaces. However, training expertise is concentrated in a relatively small number of individuals. Ideally, it would be desirable to draw upon the skills and experience of as broad a cross section of occluded space expert trainers as possible. Expertise should be solicited from those who have participated in various closure activities and from various organizations within a site, and such personnel should be tapped to provide OST training. This would ensure that occluded space surveys would benefit from information exchanged with other locations and would include formal transference of occluded space survey experiences through regular meetings focused on discussing common challenges. To ensure that the results of the OSTs are shared, they should be made part of the lessons learned program and reported as lessons learned.

Because of the complexity of the occluded space survey activity, and because it is possible for potential occluded spaces to be missed in the survey process, a second occluded space survey is carried out at the direction of management.25 The committee believes that at a minimum, a second survey is necessary. Based on a comparison of the first two surveys, management may in its judgment decide to do a third survey.

In an occluded space survey, the OST conducts a preliminary occluded space inspection and generates an occluded space task list. The occluded spaces thus identified are opened, decontaminated, and wedged open or supported to eliminate the occluded space potential. The OST then performs a physical survey by walk through. If any additional occluded spaces are identified at this stage, they are then decontaminated prior to final unventilated monitoring.


Finding 6-1. The occluded space survey is a key component of the overall monitoring strategy for closure, and it requires occluded space survey teams with a high level of expertise and significant training for proper execution.


Recommendation 6-1. Occluded space survey protocol should be standardized across the entire enterprise, and training should be strengthened, standardized across the program, and continually updated.


Finding 6-2. The expertise for occluded space survey training is concentrated in a few individuals within the overall closure activity.


Recommendation 6-2. Occluded space survey training should be diversified to include multiple experts to provide redundancy commensurate with the importance of this activity.


Finding 6-3. It is possible to fail to identify occluded spaces during the survey process, but a second survey can provide a more comprehensive identification.


Recommendation 6-3a. A second occluded space survey should be conducted by an occluded space team independent of the team that conducted the initial survey as a means of providing a higher level of confidence that all occluded spaces have been identified.


Recommendation 6-3b. A third occluded space survey should be considered based on a comparison of the first and second surveys.

Assessment of Unventilated Monitoring Testing

Upon completion of decontamination of equipment and small areas, buildings and larger areas are subjected first to ventilated and then to unventilated monitoring as described earlier. If the headspace concentrations are measured at <1 VSL in the UMT, further decontamination is not required, and the area can be made available for demolition. The unventilated environment does not represent the conditions that demolition workers would encounter, but nonetheless, it enables measurement at lower levels and thus provides a more conservative evaluation of a potentially exposed environment. The product of the UMT measurement is actually a rate at which vapor source is emitted, which is calculated by dividing the measured concentration by the time during

24

Teleconference with Brian O’Donnell, Chief, Secondary Waste, Closure Compliance and Assessments, CMA; Amy Dean, Environmental Engineer, Project Manager for Elimination of Chemical Weapons, CMA; Jeffrey Kiley, Chief Quality Assurance Office, Risk Management Directorate, CMA; and the committee; May 4, 2010.

25

Teleconference with Brian O’Donnell, Chief, Secondary Waste, Closure Compliance and Assessments, CMA; Amy Dean, Environmental Engineer, Project Manager for Elimination of Chemical Weapons, CMA; Jeffrey Kiley, Chief, Quality Assurance Office, Risk Management Directorate, CMA; and the committee; May 4, 2010.

Suggested Citation:"6 Monitoring and Analytical Issues." National Research Council. 2010. Review of Closure Plans for the Baseline Incineration Chemical Agent Disposal Facilities. Washington, DC: The National Academies Press. doi: 10.17226/12963.
×

which the sample was collected. The rate is converted to an unventilated-environment concentration by dividing the rate by the rate of air exchange in the fully ventilated configuration. It should be noted that extractive sampling requires defining a statistically valid sampling protocol, and this can be very difficult to achieve in a heterogeneous environment. The approach assumes that the concentration versus time profile generated in the UMT is linear. In actuality, the time plot usually produces a logarithmic profile, which results from the depletion of the source or reduction in the release rate as the system approaches equilibrium. A grab sample after a relatively short time will provide the initial slope and overestimate the average emission rate. Thus, UMT measured concentrations will tend to provide conservatively high emission rates for agents.26,27

The UMT is appropriately designed to protect the worker and general populations against exposure via airborne pathways. The data resulting from this approach can be used to verify that workers are not exposed to vapor concentrations in excess of the WPL and that the general population is not exposed to vapor concentrations in excess of the GPL. However, the approach does not evaluate the presence of agent in occluded spaces that were not properly identified and from which agent does not partition into the vapor phase at sufficient rates to exceed the VSL during the testing hold times. Since these residual quantities will be small, risks due to inhalation exposure will likely be negligible. In local instances, however, some dermal contact risk may arise during demolition. This should be mitigated by the fact that there will be no human contact with the demolition waste, as all handling will be done mechanically.

While the Army is applying its UMT for clearance of equipment and structures, there may be additional applications for this test. First, the committee believes that because the UMT is being used to clear buildings, the resulting debris from building demolition does not need to be subject to additional agent testing, either vapor screening or direct analysis. This assumes that the ultimate disposition of all materials is in industrial waste or industrial recycling facilities where WPLs (the focus of the UMT) will be protective and where there is no potential for dermal contact. In addition, the UMT may have potential for clearing other types of materials produced during closure—including waste, residues, and media (e.g., soil)—as being below levels of concern for agent contamination. By employing this test for waste, residues, and media as well, expensive and time-consuming direct sampling and extraction and analysis could be avoided, and the committee believes that overall closure schedules could be expedited while still protecting human health and the environment.

The Army may benefit from an evaluation of whether or not UMT is protective of human health and the environment when applied to a broader ensemble of waste, residues, and media (e.g., porous matrices). Finally, the results of the UMT measurements may be particularly valuable when correlated with agent spill or release histories. Careful comparisons of UMT results with past exposures may enable conclusions regarding agent persistence, occluded space surveying, and UMT efficacies.

It is highly probable that this approach will be protective of the workforce against airborne exposure. It should be noted that the series of protocols that culminate in the UMT provide only information on the absence or presence of agent. They are, as has been stated, aimed at protecting workers. The protocols do not provide any information about the presence of such other hazardous materials as semi-volatiles or heavy metals (e.g., mercury (Hg) or arsenic (As)), which could affect the options for disposing of materials that could be contaminated with such materials.


Finding 6-4. Unventilated monitoring testing—conducted in sequence with site exposure and spill histories, ventilated monitoring, and occluded space surveys—is appropriately designed to ensure protection of workers and the general population from agent exposure via airborne pathways. It is the final “critical step” in clearing a site for mass demolition.


Recommendation 6-4a. The Army should ensure both that the unventilated monitoring testing (UMT) protocol is uniform throughout the enterprise and that the information gained by the UMT sequence is aggressively communicated to subsequent closure sites.


Recommendation 6-4b. Locations of prior exposures and spills should be compared with the results of the unventilated monitoring testing (UMT) measurements.

26

Richard Sisson, Senior Research Scientist, Battelle, “Closure Tips and Tricks,” presentation to UMCDF, provided to the committee by Raj Malhotra, Deputy, Risk Management Directorate, CMA, via email to Nancy Schulte, study director, May 3, 2010.

27

CAMDS/TOCDF Closure Team, URS, “CAMDS/TOCDF Closure Status Implementing Programmatic Closure Approach,” presentation to the committee, January 27, 2010.

Suggested Citation:"6 Monitoring and Analytical Issues." National Research Council. 2010. Review of Closure Plans for the Baseline Incineration Chemical Agent Disposal Facilities. Washington, DC: The National Academies Press. doi: 10.17226/12963.
×

Correlation (or not) of past exposure events with UMT release rates could provide valuable insight into residual contamination, effectiveness of occluded space surveys, and UMT efficacy.


Finding 6-5. The unventilated monitoring testing sequence does not protect against dermal contact arising from waste contaminated with small quantities of agent that could be sequestered in occluded spaces. Worker protection against this risk is reliant on the occluded space surveys and on the all-mechanical handling of the demolition wastes.


Recommendation 6-5. Worker training should reinforce the use of proper protective measures against dermal contact even where vapor space monitoring shows no inhalation risk.


Finding 6-6. The monitoring program is appropriately focused on agent. Agent hydrolysis products are non-toxic or have low toxicity, with the salient exception of EA-2192 (see discussion earlier in this chapter), which does not have probable exposure routes and hence does not pose a significant risk. Other waste components (e.g., Hg and As) may affect ultimate disposal of waste materials and debris, but these can be managed within existing waste disposal rules.


Recommendation 6-6. The Army should ensure that procedures are in place to adequately analyze for other waste components that may affect ultimate disposal of waste materials and debris.


Finding 6-7. The unventilated monitoring testing can potentially be used for screening many different types of closure waste, residues, and media as being below levels of concern for the agents. Additional evaluations may demonstrate that vapor screening will meet regulatory approval in states in which it will be used to characterize debris for disposal, and they may determine whether the method is protective against dermal exposure.


Recommendation 6-7. The Army should consider conducting additional evaluations for two reasons: to demonstrate that vapor screening will meet regulatory approval in all states in which it will be used to characterize debris for disposal, and to determine whether the method is protective of human health and the environment for waste, residues, and media.


Finding 6-8. Some analytical method modifications may be needed to achieve state-specific closure and disposition standards, and in such cases, significant time and effort may be required for these modifications and for achieving regulatory approval.


Recommendation 6-8. Where method modification is needed, the Army should begin the modification and approval process as early as possible. In all cases, the Army should present its method modifications plans, including acceptance criteria, to the regulatory authority before method modification begins to gain preliminary approval. In addition, where method modifications at individual baseline facilities appear to be similar, the Army should coordinate its method modification activities among the sites to avoid duplication of efforts.

REFERENCES

Battelle Memorial Institute. 2010. Occluded Space Survey Plan Revision A. Columbus, Ohio: Battelle Memorial Institute.

Bechtel. 2006. Attachment VII. DWO18941 Occluded Space Survey. Gunpowder, MD: Bechtel.

Bechtel Aberdeen. 2007. 24719-100-30L-B93H-00009—Revision 0 Aberdeen Chemical Agent Neutralization Facility RCRA Closure Certification Report. APG Edgewood Area, MD: Bechtel Aberdeen.

EG&G Defense Materials, Inc. 2009a. CAMDS Due Diligence Review Contamination History Review. Stockton, Utah: EG&G Defense Materials, Inc.

EG&G Defense Materials, Inc. 2009b. Chemical Agent Munitions Disposal System (CAMDS) Closure Verification Sampling and Analysis Plan (Draft). Stockton, Utah: EG&G Defense Materials, Inc.

Federal Register. 2003a. Final Recommendations for Protecting Human Health from Potential Adverse Effects of Exposure to Agents GA (tabun), GB (sarin), and VX. Federal Register 68(196): 58348-58351.

Federal Register. 2003b. Proposed Airborne Exposure Limits for Chemical Warfare Agents H, HD, and HT (sulfur mustard). Federal Register 68(140): 43356-43357.

Groenewold, G. 2010. Degradation Kinetics of VX. Main Group Chemistry. In press.

Herbert, J. 2010. PRP-CAM-004—Occluded Space Process. Stockton, Utah: URS, EG&G Division.

Herbert, J. 2009. Unventilated Monitoring Prerequisites and Conduct to Support Closure. Stockton, Utah: URS, EG&G Division.

Kaaijk, J., and C. Frijlink. 1977. Degradation of S-2-di-isopropylaminoethyl O-ethyl methylphosphonothioate in Soil. Sulphur-Containing Products. Pesticide Science 8(5): 510-514.

Munro, N., S. S. Talmage, G. D. Griffin, L. C. Waters, A. P. Watson, J. F. King and V. Hauschild. 1999. Environ. Health Perspect. 107:933-974.

NRC (National Research Council). 2005a. Impact of Revised Airborne Exposure Limits on Non-Stockpile Chemical Materiel Program Activities. Washington, D.C.: The National Academies Press.

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×

NRC. 2005b. Monitoring at Chemical Agent Disposal Facilities. Washington, D.C.: The National Academies Press.

Parsons. 2009. Final Clearance Report to Support Termination of Engineering Controls and Mass Demolition of the UB. Indianapolis, IN: Parsons.

Reutter, S. 1999. Hazards of Chemical Weapons Release during War: New Perspectives. Environmental Health Perspectives 107(12): 985-990.

URS. 2009. CAMDS Chemical Test Facility (CTF) Building C-7071 Decommissioning Work Package (DWP). Stockton, Utah: EG&G Division.

Verweij, A., and H. Boter. 1976. Degradation of S-2-Di-isopropylaminoethyl O-ethyl Methylphosphonothioate in Soil: Phosphorus-Containing Products. Pesticide Science 7(4): 355-362.

Washington Demilitarization Company. 2010. PB-PL-110 Facility Closure Plan (Draft). White Hall, AR: Washington Demilitarization Company.

Yang, Y.-C., L. Szafraniec, W. Beaudry, and D. Rohrbaugh. 1990. Oxidative Detoxification of Phosphonothiolates. Journal of the American Chemical Society 112(18): 6621-6627.

Suggested Citation:"6 Monitoring and Analytical Issues." National Research Council. 2010. Review of Closure Plans for the Baseline Incineration Chemical Agent Disposal Facilities. Washington, DC: The National Academies Press. doi: 10.17226/12963.
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×
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×
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Suggested Citation:"6 Monitoring and Analytical Issues." National Research Council. 2010. Review of Closure Plans for the Baseline Incineration Chemical Agent Disposal Facilities. Washington, DC: The National Academies Press. doi: 10.17226/12963.
×
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×
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Suggested Citation:"6 Monitoring and Analytical Issues." National Research Council. 2010. Review of Closure Plans for the Baseline Incineration Chemical Agent Disposal Facilities. Washington, DC: The National Academies Press. doi: 10.17226/12963.
×
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Suggested Citation:"6 Monitoring and Analytical Issues." National Research Council. 2010. Review of Closure Plans for the Baseline Incineration Chemical Agent Disposal Facilities. Washington, DC: The National Academies Press. doi: 10.17226/12963.
×
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Suggested Citation:"6 Monitoring and Analytical Issues." National Research Council. 2010. Review of Closure Plans for the Baseline Incineration Chemical Agent Disposal Facilities. Washington, DC: The National Academies Press. doi: 10.17226/12963.
×
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Suggested Citation:"6 Monitoring and Analytical Issues." National Research Council. 2010. Review of Closure Plans for the Baseline Incineration Chemical Agent Disposal Facilities. Washington, DC: The National Academies Press. doi: 10.17226/12963.
×
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Suggested Citation:"6 Monitoring and Analytical Issues." National Research Council. 2010. Review of Closure Plans for the Baseline Incineration Chemical Agent Disposal Facilities. Washington, DC: The National Academies Press. doi: 10.17226/12963.
×
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×
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This book responds to a request by the director of the U.S. Army Chemical Materials Agency (CMA) for the National Research Council to examine and evaluate the ongoing planning for closure of the four currently operational baseline incineration chemical agent disposal facilities and the closure of a related testing facility. The book evaluates the closure planning process as well as some aspects of closure operations that are taking place while the facilities are still disposing of agent. These facilities are located in Anniston, Alabama; Pine Bluff, Arkansas; Tooele, Utah; and Umatilla, Oregon. They are designated by the acronyms ANCDF, PBCDF, TOCDF, and UMCDF, respectively. Although the facilities all use the same technology and are in many ways identical, each has a particular set of challenges.

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